Recommended way for building percussion kit when instrument is not provided by Dorico?

I started mapping NI Komplete Cuba. Their Conga set has 3 congas: Tumba, Conga and Quinto.

The problem is, Dorico only provides two congas: high and low. The way Dorico works is that percussion map is not related to a kit, but to the underlying instruments*. That means I can’t use two high congas, as that would map one instrument to two midi notes. In addition, one can not add custom instruments (without editing the factory xmls).

So, what is the “officially” recommended way to solve this? Is there even any other option than using some other instrument, which must not be in the VST so there is no clash in percussion map?

*I’m not sure that design is meaningful. At least for percussion kits, I think it would make more sense to have mapping done directly in the kit. In essence, percussion kit dialog should be able to do everything from start to end - defining playback techniques (even adding user defined ones if needed) and mapping them to VST, and probably on the kit level, not instrument level

Obviously it’s a real shortcoming that the way Dorico’s percussion mapping works requires you to be able to map instruments and their playing techniques definitively to specific pitches in percussion patches from sound libraries and MIDI devices, but it doesn’t yet provide you with a means of defining your own instruments. This is something that we will certainly address in future. In the meantime you will have to do what you outline, i.e. use another unused percussion instrument as a proxy for the missing conga.